Removing the Body
There are lots of references in the forum and on the R4 websites to the need to remove the body to carry out repairs to the chassis of an R4. The reality of this is that most of the crucial areas are hidden out of sight, within the faces where the shell is fixed down to the chassis, or are extremely difficult to get at, and although patching over visible rust may satisfy an MOT Inspector for another year, it will not prevent the corrosion from carrying on unseen and eventually the car may become a write off. So removal of the body tub is a must for thorough repair of the car and fortunately , although time consuming, if approached in a logical and orderly manner, it should hold no fears for a decent DIY mechanic, and even if he intends to pass on the chassis to an expert for welding, should present a significant cost saving in labour. Tools: You will need a reasonable toolkit, including a trolley jack, a socket set ,( mainly 11mm), spanners, Philips screwdrivers, an impact driver for seized fixings, and a supply of plus gas or similar ( soak any fixings for a few days before starting.) You will need to make a couple of dozen thin wooden wedges approx 10cm x 2.5cm. You will also need lifting tackle, an engine crane, or several hefty friends. There are some diagrams in the Haynes manual that will help you spot all of the bolts. Ideally, one should remove as many components from the tub as possible, to reduce overall weight and make the final lift easier. Some do leave on some components such as doors , and how light you need it to be depends on how you are lifting the tub finally, albeit, leaving it too heavy will make it want to distort that much more, when hoisted in the air. *Position the car so that you can pull the chassis forwards on its wheels into clear space. *Start at the front, disconnect and remove the battery. Drain the cooling system. Disconnect the front lights and tie back the wires in a plastic bag. Unbolt the bonnet lid and the safety wires and remove it out of the way. Disconnect heater hoses, clutch, accelerator and choke linkages and tie back out of the way. Disconnect any earths or other wires attached to ancillaries on the engine. Tag all connections so that you don’t forget what goes where. Use a digital camera for any awkward areas that you might not remember. Ideally drain the fuel tank as well (siphon if your tank doesn’t have a drain plug) *Remove jack and brace from their clips. Disconnect expansion tank and windscreen washer bottle. *Disconnect the exhaust from the manifold and pull it clear. Ideally remove the clamp and take off the downpipe completely, but this may be rusted in place and you may have to manipulate the inner wing at the next stage to release it. *Disconnect the rear fuel and brake lines within the engine compartment, again, these are fed through a hole in the inner wings. Watch out for brake fluid drips. *Remove the outer wings by unbolting, and releasing the self tappers within the car that hold the rear edge of the wing in place (take the front parcel shelves out of the car first, this will make access easier). *You can now unbolt the inner wings from the front and main chassis members. You can also remove the bolts that secure them to the bulkhead, from inside the footwells of the car and remove them altogether, although some do prefer to leave them in place and attached. This must, however, make the final lift more difficult, unless you have the means to lift it dead level and I recommend taking them off (the rest of this WIKI assumes that you have) *Disconnect steering shaft at universal joint and operating rods for gearshift and handbrake (if front wheel braked). *Inside, remove the seats. This won’t help with the weight, but makes access to some of the mounting bolts easier, will mean that you don’t have to lift the tub so high when it is removed, and you probably will want them out of way when welding etc. anyway. Remove seat belts. *Remove the doors and tailgate. In earlier cars these just lift off their hinges after a small retaining nut is removed from the top hinge. The glass in these is a substantial weight. *Rear wings are optional really, but the fuel filler hose and breather need to be detached, and the wire to the fuel tank sender located and disconnected if possible (I chopped mine and replaced it). I’d also take off the rear lights since these are vulnerable to damage when lifting. *If you have a later model with a floor mounted handbrake, then you will also need to disconnect the hand brake cables from the rear swinging arm assemblies. *Bolts next. You will need an 11mm socket, and spanners for most of these and some may be corroded solid, so an angle grinder with a thin cutting disc in it will be useful. *Starting again at the front, there are holding down nuts and bolts along the flanged joint between the chassis and the upper bulkhead and also setscrews through brackets onto the inner end of each chassis rail, all accessed from above. You may have to chop the flange fittings if they are badly rusted. *Release the bolts along each cill inside the base of the door opening (remove the plastic kick plates first, if fitted) and behind the A panel alongside the footwell. There are also captive bolts into the footwell at the base of the bulkhead just below the heater, accessed from inside the car. *There are further bolts along the front edge of the boot floor which is part of the tub. The centre one of these is a long bolt right through to the petrol tank flange under the car and needs an assistant or some nifty work with Plus Gas and a mole wrench. *Leave the spare wheel in place for the moment. Why will become evident. *At the extreme rear of the car are two further nuts and bolts, heads visible inside the car just inside the tailgate and nuts accessed through holes in the chassis member. Remove these with a socket underneath and a spanner on top. If you have rear seat belts, then these too need removing from the twin fixings in the boot floor just behind the seat. If not, there may be plastic screw in plugs which also need taking out. *In addition to these bolts, the two units are sealed together with a heavy adhesive mastic and this seal needs to be broken especially across the width of the front edge of the boot, since it will distort quite badly if the seal is just left untouched. *My solution was a series of timber wedges, cut from scrap wood, about 10cm long. Tap one gently initially a centimetre or so under the flange at each bolt position. If you have a heat gun and especially if the weather is cold, warm up the main chassis to body joint with that also. *Now get your trolley jack with a suitable wooden pad and locate it under the centre of the spare wheel, apply sufficient uplift to start to take the weight off the rear suspension. Go round tapping in your wedges and heating the joint and you should start to see movement, ease up the jack a bit more, tap in your wedges further and the weight of the chassis, should start to spllt the joint open slowly. If it doesn’t come, or starts to tilt, make sure that you have no remaining bolts in place, or that someone hasn’t welded the two together locally with a patch repair. If the latter is the case, deploy the cutting disc again. *Now for the lift. I had access to a gantry and wrapped some straps through the door apertures onto the hook and hoisted away. Three or four strong men can achieve the same end, or you can jack up onto trestles supporting beams under the tub and pull the chassis out. *The body needs to sit on blocks on the mating faces along the cills, preferably under the pillars, otherwise the cill will be damaged. A good trick is to concoct a simple timber dolly on some heavy duty castors so that you can wheel it around. *Replacement and reassembly is, in the words of Mr Haynes, a reversal of the process, but with a couple of variables and before you do proceed, look at any other dismantling and renovation that might be needed, particularly around rear suspension and petrol tank. Whatever is needed it is easier done now. If the brake and fuel lines were removed during welding, make sure that they are clipped back along the vertical face of the main chassis member. *Now, clean off all of the old mastic from the mating faces and give it all a good coat of rust proofing paint. Apply new mastic. UPOL make a good product called Tiger Seal. This isn’t cheap but it has adhesive qualities which help with the overall strength of the assembly. There are also proprietary mastic sealing strips that can be used. Two large cartridges of mastic will do the trick. I think there is about eight metres of strip used if something off the roll is employed. Kitchen type cartridge sealant is not suitable. *Suspend the body about an inch or so above the chassis. Once stuck it may prove awkward to move and may waste expensive sealant, so take a few thin-ish long shafted screwdrivers and poke them through a couple of the cill bolt holes each side to allow you to get the alignment then manipulate the shell into position. Get a couple of bolts in along the cills and alignment should follow. If the body has distorted through being sat around unsupported, then you may have to use a little brute force here and there. The tub is very light and flexible when loose. On mine, the front chassis rail mounting took some lining up (only by a couple of mm, but enough to make it hard work) *Tighten everything down progressively, keeping an eye on alignments etc. as you go. Clean up any mastic that squidges out. Now the disclaimers You will need proper protective gear, to include heavy duty gloves, safety shoes, safety specs especially when cutting with the grinder and either tie back any long hair or wear a woolly hat to contain it all. Take off your tie!!. All the usual workshop safety rules apply, don’t crawl underneath a jacked up car or suspended body tub, keep your fingers out of any open joints whilst prising the shell off the chassis and generally use your common sense. This process has worked for me and many others, but I accept no liability for any misadventures that arise as a result of your following this routine. Category:Chassis